A vibration damping material has been conventionally used as a material for absorbing vibration energy in parts, where vibration occurs, in a vehicle, a railway car, an aircraft, a household appliance, an OA apparatus, a precision apparatus, a building machine, a construction/building, shoes, a sport gear, and the like.
As a material for absorbing vibration energy such as a vibration damping material, there has been known a soft vinyl chloride-based resin obtained by adding a plasticizer to a vinyl chloride-based resin. The soft vinyl chloride-based resin is designed so as to attenuate the vibration energy by consuming the vibration energy as frictional heat in the resin. However, the absorption and attenuation of the vibration energy by the resin is still insufficient.
Besides, rubber materials such as butyl rubber and NBR have been widely used as the vibration damping material, because those rubber materials are outstanding in terms of processability, mechanical strength, and cost. However, though those rubber materials have the best attenuation performance (transfer-insulating performance or transfer-moderating performance of vibration energy) among general polymeric materials, the vibration damping ability (absorbability of vibration energy) thereof is too low to use the rubber materials solely as the vibration damping material. Thus, to apply the rubber materials, for example, to vibration isolation structure for buildings or apparatuses, the rubber materials have been used in a composite form such as a laminate of the rubber material and a steel plate, or a vibration damping structure formed in combination of the laminate and a lead core that absorbs vibration energy by plastic deformation or an oil damper.
The conventional rubber materials could not be solely used as the vibration damping material as described above, and hence the rubber materials were required to have a composite form. Thus, the vibration isolation structure was inevitably complicated. It has been consequently demanded to enhance the vibration damping abilities of the vibration damping materials themselves and the rubber materials themselves.
In addition, as the vibration damping material, a polyester resin composition having a moiety where the number of carbon atoms between ester linkages in a main chain is odd number is disclosed (JP 2006-052377 A). The polyester resin composition has a good vibration damping ability at room temperature or close to the room temperature, and thus the composition is a promising material as the vibration damping material. However, because a carbon powder is mainly used as a conductive material in the polyester resin, and dispersed with a mica powder or the like, the vibration damping material turns black or brown. Thus, there is a problem in that the composition is unlikely to be used in applications and parts that require various color tones while the vibration damping ability is maintained and improved. Moreover, demanded is a vibration damping material that exhibits a good vibration damping ability in a wider range of frequency.